Despite warnings against the use of drugs during pregnancy, there are situations in which the developing young are exposed to these potential hazards. Two classes of psychoactive drugs currently being used in pregnant women for medical and nonmedical reasons are narcotics and anticonvulsants. The proposed research aims at investigating the effects of these classes of compounds in doses and dosage regimens analogous to human use on the general and neuromotor development of animal offspring. In contrast to previous work, pharmacological activity will be evaluated in the maternal organisms and correlated with effects observed in the offspring. Moreover, experimental manipulations will be performed to separate primary effects on the developing young from effects mediated through the maternal animal. This combination of procedures should provide valuable information regarding the effects of these classes of compounds as well as the significance of the effects relative to human use.